No, the Cerbera I speak of is not the Speed 12. What I heard of used a less potent engine and retained Cerbera everything else (except pertinent changes to accomodate the new engine, i.e. suspension). It was rumored above 600HP, but nowhere near the speed 12.
As far as I know, the Cerbera is the only current model that has come to the states, but I've heard both ways about the Griffith.